Convert a pOH value of 12.1 to [H3O+].
To convert pOH to [H3O+], you can use the following equation:
pH + pOH = 14
Now, convert the pOH value to pH:
pH = 14 - pOH
pH = 14 - 12.1
pH = 1.9
Now that you have the pH value, you can convert it to [H3O+] using the formula:
[H3O+] = 10^(-pH)
[H3O+] = 10^(-1.9)
[H3O+] = 1.26 x 10^(-2) mol/L
Therefore, the [H3O+] concentration for a pOH of 12.1 is 1.26 x 10^(-2) mol/L.